title: Characterization of CENH3 proteins and centromere-associated DNA sequences in diploid and allotetraploid Brassica species.
abstract: CENH3 is a centromere-specific histone H3 variant and has been used as a marker to identify active centromeres and DNA sequences associated with functional centromere/kinetochore complexes. In this study, up to four distinct CENH3 (BrCENH3) cDNAs were identified in individuals of each of three diploid species of Brassica. Comparison of the BrCENH3 cDNAs implied three related gene families: BrCENH3-A in Brassica rapa (AA), BrCENH3-B in B. nigra (BB), and BrCENH3-C in B. oleracea (CC). Each family encoded a histone fold domain and N-terminal histone tails that vary in length in all three families. The BrCENH3-B cDNAs have a deletion of two exons relative to BrCENH3-A and BrCENH3-C, consistent with the more ancient divergence of the BB genome. Chromatin immunoprecipitation and immunolabeling tests with anti-BrCENH3 antibodies indicated that both centromeric tandem repeats and the centromere-specific retrotransposons of Brassica are directly associated with BrCENH3 proteins. In three allotetraploid species, we find either co-transcription of the BrCENH3 genes of the ancestral diploid species or gene suppression of the BrCENH3 from one ancestor. Although B genome centromeres are occupied by BrCENH3-B in the ancestral species B. nigra, in allotetraploids both BrCENH3-A and BrCENH3-C proteins appear to assemble at these centromeres.
authors.affiliation: National Maize Improvement Center of China, Key Laboratory of Crop Genetic Improvement and Genome of Ministry of Agriculture, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University.
authors.forename: Guixiang
authors.initials: G
authors.lastname: Wang
authors.forename: Qunyan
authors.initials: Q
authors.lastname: He
authors.forename: Fan
authors.initials: F
authors.lastname: Liu
authors.forename: Zhukuan
authors.initials: Z
authors.lastname: Cheng
authors.forename: Paul B
authors.initials: PB
authors.lastname: Talbert
authors.forename: Weiwei
authors.initials: W
authors.lastname: Jin
mesh_terms: D000220:Adaptation, Biological; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000378:metabolism; D001937:Brassica / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D002503:Centromere / Q000737:chemistry* / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli; D019143:Evolution, Molecular; D006657:Histones / Q000235:genetics* / Q000378:metabolism; D018386:Kinetochores / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids; D011003:Ploidies; D020033:Protein Isoforms / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics* / Q000378:metabolism; D018626:Retroelements / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D020080:Tandem Repeat Sequences
chemical_list: D000906:Antibodies; D018744:DNA, Plant; D006657:Histones; D010940:Plant Proteins; D020033:Protein Isoforms; D011994:Recombinant Proteins; D018626:Retroelements